Heaters for hot runner nozzles are known. In some applications the nozzle heater is embedded in the nozzle body or attached to the nozzle body. In other applications the nozzle heater is composed of a support element such as a sleeve or a tube and a heating element is coupled, for example secured to the inside or outside of the sleeve or tube.
When the hot runner nozzle is placed in a hot runner system, the nozzle and components of the nozzle make direct contact with parts of the hot runner system and parts of the mold that are colder than the nozzle and parts associated with the hot runner nozzle. These contacts cause a heat loss and this creates a non-uniform heat profile along the nozzle.
There is a need to further improve the heaters used for injection molding hot runners and meet specific challenges such as mentioned below.
The heat profile can be improved by a better design of the heater and also by providing a better clamping/connection of the nozzle heater to the nozzle.
Also the heater design may need to take into consideration the heating requirements for several applications and for several dimensions of the nozzle.
If a nozzle heater fails or its performance is not acceptable there is a need to replace the heater with minimum effort and in a record time from the front of the nozzle.
All of these also requires that the heater should be easier to manufacture and within acceptable tolerances.
There is also a need to develop a manufacturing process for nozzle heater assemblies that use less raw materials and simpler and fewer manufacturing steps that all together reduce the energy consumption significantly.